A single point mutation (C>T) was engineered in exon 3, changing arginine codon 98 into a cysteine codon (p.Arg98Cys). The loxP site flanked neomycin resistance gene cassette that was inserted into intron 3 was removed through cre-mediated recombination. This mutation emulates a mutation found in some human early onset Charcot-Marie-Tooth disease type 1B (CMT1B) patients. (J:241742)